Vapor deposition process for the manufacture of coated particles

Abstract

A process for conducting vapor phase deposition is disclosed. The process separates a series of reactions through a sequence of reaction reservoirs. The reactor includes a reactive precursor reservoir beneath a powder reservoir separated by valve means. A reactive precursor is charged into the reactive precursor reservoir and a powder is charged into the powder reservoir. The pressures are adjusted so that the pressure in the reactive precursor reservoir is higher than that of the powder reservoir. The valve means is opened, and the vapor phase reactant fluidized the powder and coats its surface. The powder falls into the reactive precursor reservoir. The apparatus permits vapor phase deposition processes to be performed semi-continuously.

The invention claimed is: 
     
       1. An atomic or molecular layer deposition process for coating the interior pores and exterior surfaces of a substrate, comprising:
 (a) placing a substrate comprising pores into a substrate reservoir through a first valve, wherein said substrate reservoir is operatively connected to, and initially isolated from, a first precursor reservoir, by a second valve; 
 (b) closing said first valve; 
 (c) producing a first reactive precursor vapor in said first precursor reservoir under pressure conditions sufficient to:
 i. cause the first reactive precursor vapor to flow into the substrate reservoir upon opening the second valve; 
 ii. adequately saturate the surface area of the substrate with the first reactive precursor; 
 iii. deposit a layer of the first reactive precursor on the interior pores and exterior surfaces of said substrate; 
 
 (d) opening said second valve and allowing the pressure in the combined volumes of the substrate reservoir and the first precursor reservoir to equilibrate; 
 (e) conveying the substrate from the substrate reservoir into the first precursor reservoir, thereby producing a first reactive precursor coated substrate; 
 (f) removing excess first reactive precursor and gaseous reaction byproducts; and 
 (f) contacting the first reactive precursor coated substrate with a second reactive precursor vapor under conditions sufficient to produce an atomic or molecular layer deposition coated substrate semi-continuously. 
 
     
     
       2. The process of  claim 1 , wherein the substrate is a powder. 
     
     
       3. The process of  claim 2 , wherein the pressure conditions are sufficient to at least partially fluidize the powder. 
     
     
       4. The process of  claim 1 , wherein the first precursor reservoir is located below the substrate reservoir. 
     
     
       5. The process of  claim 4 , wherein the conveying comprises allowing the substrate to fall from the substrate reservoir into the first precursor reservoir. 
     
     
       6. The process of  claim 1 , wherein the first precursor reservoir has a pressure higher than the pressure in the substrate reservoir. 
     
     
       7. The process of  claim 1 , wherein the contacting comprises
 producing a second reactive precursor vapor in a second precursor reservoir that is operatively connected to the first precursor reservoir under conditions sufficient to:
 i. cause the second reactive precursor vapor to flow into the first precursor reservoir upon opening a third valve; 
 ii. adequately saturate the surface area of the first reactive precursor coated substrate with the second reactive precursor; 
 iii. deposit a layer of the second reactive precursor on the interior pores and exterior surfaces of the first reactive precursor coated substrate; and 
 
 conveying the first reactive precursor coated substrate from the first precursor reservoir into the second precursor reservoir, thereby producing the atomic or molecular layer deposition coated substrate from the reaction between the second reactive precursor and the first reactive precursor that is on the surface of the first reactive precursor coated substrate. 
 
     
     
       8. The process of  claim 7 , wherein the second precursor reservoir is located below the first precursor reservoir. 
     
     
       9. The process of  claim 8 , wherein the conveying comprises allowing the first reactive precursor coated substrate to fall from the first precursor reservoir into the second precursor reservoir. 
     
     
       10. An atomic or molecular layer deposition process for coating the interior pores and exterior surfaces of a substrate, comprising:
 (a) placing a substrate comprising pores into a substrate reservoir, wherein the substrate reservoir is operatively connected to, and initially isolated from, a first precursor reservoir, by a valve; 
 (b) producing a first reactive precursor vapor in the first precursor reservoir under pressure conditions sufficient to:
 i. cause the first reactive precursor vapor to flow into the substrate reservoir upon opening the valve; 
 ii. adequately saturate the surface area of the substrate with the first reactive precursor; 
 iii. deposit a layer of the first reactive precursor on the interior pores and exterior surfaces of the substrate; 
 
 (c) opening the valve and conveying the substrate from the substrate reservoir into the first precursor reservoir, thereby producing a first reactive precursor coated substrate; and 
 (e) contacting the first reactive precursor coated substrate with a second reactive precursor vapor under conditions sufficient to produce an atomic or molecular layer deposition coated substrate semi-continuously. 
 
     
     
       11. An atomic or molecular layer deposition process for coating the interior pores and exterior surfaces of a substrate, comprising:
 (a) placing a substrate comprising pores into a substrate reservoir, wherein the substrate reservoir is operatively connected to, and initially isolated from, a first precursor reservoir, by a first valve; 
 (b) producing a first reactive precursor vapor in the first precursor reservoir under pressure conditions sufficient to:
 i. cause the first reactive precursor vapor to flow into the substrate reservoir upon opening the first valve; 
 ii. adequately saturate the surface area of the substrate with the first reactive precursor; 
 iii. deposit a layer of the first reactive precursor on the interior pores and exterior surfaces of the substrate; 
 
 (c) opening the first valve and conveying the substrate from the substrate reservoir into the first precursor reservoir, thereby producing a first reactive precursor coated substrate; 
 (e) producing a second reactive precursor vapor in a second precursor reservoir that is operatively connected to the first precursor reservoir under conditions sufficient to:
 i. cause the second reactive precursor vapor to flow into the first precursor reservoir upon opening a second valve; 
 ii. adequately saturate the surface area of the first reactive precursor coated substrate with the second reactive precursor; 
 iii. deposit a layer of the second reactive precursor on the interior pores and exterior surfaces of the first reactive precursor coated substrate; and 
 
 (f) opening the second valve and conveying the first reactive precursor coated substrate from the first precursor reservoir into the second precursor reservoir, thereby producing the atomic or molecular layer deposition coated substrate from the reaction between the second reactive precursor and the first reactive precursor that is on the surface of the first reactive precursor coated substrate. 
 
     
     
       12. The process of  claim 10 , wherein the first precursor reservoir has a pressure higher than the pressure in the substrate reservoir. 
     
     
       13. The process of  claim 11 , wherein the first precursor reservoir has a pressure higher than the pressure in the substrate reservoir. 
     
     
       14. An atomic or molecular layer deposition process for coating the interior pores and exterior surfaces of a substrate, comprising:
 (a) placing a substrate comprising pores into a substrate reservoir, wherein the substrate reservoir is operatively connected to, and initially isolated from, a first precursor reservoir; 
 (b) producing a first reactive precursor vapor in the first precursor reservoir by pulsing under pressure conditions sufficient to:
 i. adequately saturate the surface area of the substrate with the first reactive precursor; 
 ii. deposit a layer of the first reactive precursor on the interior pores and exterior surfaces of the substrate; 
 
 (c) conveying the substrate from the substrate reservoir into the first precursor reservoir, thereby producing a first reactive precursor coated substrate; and 
 (e) contacting the first reactive precursor coated substrate with a second reactive precursor vapor under conditions sufficient to produce an atomic or molecular layer deposition coated substrate.